The present invention relates to an improvement of a device for making a magnetic disc cartridge, which is so called a floppy disc, and more particularly to an improvement of a device for adhering a liner sheet to a cover jacket which encloses the floppy disc.
A floppy disc comprises a magnetic disc and a jacket enclosing the magnetic disc. Said jacket is composed of a cover sheet made of a thermal plastic resin material such as polyvinyl chloride and a liner sheet made of a non woven fabric of synthetic fiber of rayon or polypropylene which is attached to the inner face of the cover sheet to stabilize rotation of the magnetic disc.
Conventionally, in the process of manufacturing such a floppy disc, said liner sheet is placed and adhered onto the cover sheet by heat melting adhesion. In this adhesion process, in order to avoid undesired thermal deformation of the liner sheet due to an excessive temperature rise, such a hot melting adhesion must be performed rapidly. However, since the hot melting adhesion is made by passing the liner sheet and the cover sheet between a pair of heat rollers rotating in a high speed during the hot melting adhesion, the liner sheet is apt to be displaced from correct position due to vibration of the heat rollers in addition to vibration occurring during transfer of the liner sheet and the cover sheet. It is noted that the liner sheet is made of a non woven light fabric and is placed on a flat smoothed surface of the cover sheet, the liner sheet can be easily displaced from position by various vibrations as mentioned above.
On the other hand, in the magnetic disc cartridge, the liner sheet must be laid uniformly inside the cover sheet without being folded and overlapped, so that a magnetic disc can rotate smoothly. In a case where the liner sheet is displaced from position in the process of adhesion onto the one surface of the cover sheet, which is in turn formed into a jacket, the liner sheet may partly be folded or undesirably overlapped, thus causing the disc to be prevented from a smooth rotation.
Accordingly, an object of the present invention is to provide a device for making of magnetic disc cartridge which prevents the displacement of the liner sheet from the correct position in the process of adhering the liner sheet onto the cover sheet.
Another object of the present invention is to provide a device for making a magnetic recording disc cartridge wherein a liner sheet is not folded in an undesirable manner during the process of adhesion of the liner to a cover sheet of the cartridge.
A further object of the present invention is to provide a device for making a magnetic recording disc cartridge in accordance with a method of the present invention.
According to the present invention, there is a device for making a magnetic recording disc cartridge having a cover jacket in the form of an enclosure with a drive shaft insertion hole and a recording head access hole defined therein and a magnetic recording disc which is rotatably enclosed in the enclosure, said cover jacket being composed of a cover sheet of a generally elongated rectangular shape with a liner laid on the surface of the cover sheet. The jacket is formed by folding the cover sheet with a liner along a line crossing in a direction along the short side of the cover sheet in such a manner that both portions of the liner positioned on both sides of the folded liner are opposed to each other in the enclosure.
The device comprises a feed table for placing the cover sheet with the liner thereon and first adhering means having a plurality of heating chips for adhering said liner to the cover sheet by heat melting adhesion, the heating chips are vertically movably disposed above the feed table. First transferring means are provided for transferring the cover sheet with the liner from an initial position remote from the first adhering means on the feed table to such a position that the front peripheral edge portion of the liner is placed below the heating chips of the first adhering means. Means for reciprocally moving the heating chips in a vertical direction are provided. The cover sheet with the liner is transferred to such a position that the front peripheral edge portion of the liner is placed below the heating chips of the first adhering means by said first transferring means and in turn the heating chips of the first adhering means are lowered to contact on the liner from above to preliminarily adhere the liner to the cover sheet by a plurality of spots on the front peripheral edge thereof. The device further comprising second ahdering means for adhering the liner to the cover sheet by heat melting adhesion around the respective patterns of the drive shaft insertion hole and the recording head access hole, second transferring means for transferring the cover sheet with the liner to a position below the second adhering means after said preliminary adhering is perfected, third adhering means for adhering the liner to the cover sheet by heat melting adhesion over a plurality of predetermined linear patterns on the liner and third transferring means for transferring the cover sheet with the liner from the second adhering means to the third adhering means.
One advantage of the present invention is to prevent a displacement of the liner and the cover sheet from the correct position during the process of making a magnetic recording disc cartridge even if there are various vibrations in the feeding mechanism for transferring the cover sheet with the liner from one process to the subsequent process rapidly, thereby assuring a manufacturing of the magnetic recording disc cartridge without undesired folded portion or overlapped portion of the liner in a cartridge so that smooth rotation of the magnetic recording disc can be obtained.
Other advantage of the present invention is to prevent an undesired separation of the liner from the cover sheet in the peripheral portions around the respective drive shaft insertion holes and the head across holes when they are punched.